The topic of German-Jewish relations continues to exercise the labours of historians and sociologists. Recent fiction, notably in German, has been obsessed with the background to and after-life of the Holocaust. The opening of the Jewish Museum in Berlin, together with the interminable, acrimonious debate over a national memorial to Jewish victims, heightens attention, both German and international.

In no other nation, after their emancipation from the ghetto, did Jews experience a comparable flowing in the life of science and the intellect, in many branches of the arts and in the business world. In none was the end of co-existence more hideous and irreparable. What, in God's name - that cant phrase being so apposite - went wrong?

Fritz Stern has devoted a lifetime of thought, research and publication to this question. His studies of the role of Jewish finance in the construction of Bismarck's empire, his essays on the apocalyptic strains in German political theory and on the singular destiny of a major power which had entered so late into European affairs, are of the highest distinction. Related through his family to many of the seminal figures in German science and public affairs, Professor Stern has been an analyst and witness of exceptional authority.

In this collection of essays, reviews and addresses, the virtues of clarity, of humane poise, of extensive knowledge scrupulously enlisted, are manifest. A certain twilit sadness inevitably colours his backward look. How is one to balance, let alone relate, the splendour that was Goethe and Beethoven and Kant to the febrile, formidably creative climate of Weimar and the blackness that followed? Despite unquestionable prejudice and mundane discriminations, 'Einstein's German world was one in which Christians and Jews [or individuals of Jewish descent] lived and worked together'. What roads led to Auschwitz?

Rightly, Stern focuses on the exact and applied sciences. In numerous branches, in academic and applied research, in attributions of official reward, German science throughout the later nineteenth and early twentieth centuries came close to leading the civilised world. In this pre-eminence, the genius of Jewish scientists and the largesse of Jewish donors played a salient role. As Stern puts it: 'The wildly anti-Semitic kaiser had a weakness for rich Jews, and for his weakness he was vilified by rabid, incorruptible anti-Semites.' (The ironic equity of the sentence is wholly characteristic.)

The principal text in this gathering is a twofold portrayal of Fritz Haber and Albert Einstein. It is their complex, ultimately doomed relationship which epitomises that of Germany and its Jews. Haber was an organic chemist and biochemist of the very first rank. Endowed with devouring ambition and almost demonic capacities for hard work, he made a number of discoveries which did change history. The fixation of nitrogen from the air provided Germany with the ammoniac need for fertilisers, for high explosives and for poison gas during the First World War.

It was Haber, more than any other scientist, who cemented the decisive alliance between industry and research, between academic and laboratory-results of Nobel stature and their industrial application on a vast scale. Much of today's industrial-military complex, together with the entire concept of research and development in academic institutes, derives from Haber's rare combination of abstract insight, experimental virtuosity and managerial adroitness. The man paid a fearful price, losing his sons in successive wars to whose technological ferocity he had so prodigally contributed.

Haber's admiration for Einstein was boundless. Einstein, whose private complications Stern alludes to with illuminating tact, responded. But the matter of Germany came to divide them. Haber was, like so many converted Jews, a super-patriot, wholly devoted to German nationalism and ready, almost to the last moment, to allow even Hitlerism the benefit of the doubt. He strove to keep Einstein in a darkeningly anti-Semitic post-1918 Berlin.

Einstein's pacifism, his declared Zionist sympathies, were alien to Haber. Yet a common irony, unperceived, it would seem, by Fritz Stern, conjoins their two destinies. Haber's work on poison gas led to the Zyklon-B of the Nazi death-ovens. Einstein's identification of energy and mass led to Hiroshima. If the chemotherapy of Paul Ehrlich did, for a time, liberate human beings from syphilis, the discoveries of Haber and Einstein rendered the human condition distinctly more threatening.

In a hotly debated study, Daniel Goldhagen ruled that the Holocaust was endemic in the German character and in German history since the pogroms of the Middle Ages. Stern's review, reprinted here, shows the fallacy of the claim. French anti-Semitism was rife after the Dreyfus Affair; Jew-hatred in Austria was, continues to be, more rabid than any in Germany. None the less, Fritz Stern leaves unanswered Goldhagen's final question. With Soviet troops very near, German civilians, instead of begging forgiveness and seeking to flatter their new masters, continued to butcher Jews on their death-marches. Why? What is there in German sensibility which, however obliquely, underwrote Hitler's madness?

Fritz Stern's emphasis lies elsewhere. He looks to reconciliation both symbolic and substantive. He points to the proud record of (West) German democracy and social justice over more than half a century. Franco-German understanding and German-Polish relations are strong signs of hope. Breslau remains Stern's native ground. Einstein was far less forgiving. He did not set foot in Germany again.